[gtk+] gtkgestureswipe: Handle touchpad swipe events

[Carlos Garnacho <carlosg src gnome org>]

commit 5d17338b4d158f6b460c73b064e1c2f363007d9c
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Jul 24 13:03:09 2015 +0200

    gtkgestureswipe: Handle touchpad swipe events
    
    These will only trigger the gesture if it's been created with
    the same GtkGesture::n-points than n_fingers in the event.

 gtk/gtkgestureswipe.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkgestureswipe.c b/gtk/gtkgestureswipe.c
index 0ca5bb3..82bfba0 100644
--- a/gtk/gtkgestureswipe.c
+++ b/gtk/gtkgestureswipe.c
@@ -77,6 +77,26 @@ gtk_gesture_swipe_finalize (GObject *object)
   G_OBJECT_CLASS (gtk_gesture_swipe_parent_class)->finalize (object);
 }
 
+static gboolean
+gtk_gesture_swipe_filter_event (GtkEventController *controller,
+                                const GdkEvent     *event)
+{
+  /* Let touchpad swipe events go through, only if they match n-points  */
+  if (event->type == GDK_TOUCHPAD_SWIPE)
+    {
+      guint n_points;
+
+      g_object_get (G_OBJECT (controller), "n-points", &n_points, NULL);
+
+      if (event->touchpad_swipe.n_fingers == n_points)
+        return FALSE;
+      else
+        return TRUE;
+    }
+
+  return GTK_EVENT_CONTROLLER_CLASS (gtk_gesture_swipe_parent_class)->filter_event (controller, event);
+}
+
 static void
 _gtk_gesture_swipe_clear_backlog (GtkGestureSwipe *gesture,
                                   guint32          evtime)
@@ -188,10 +208,13 @@ static void
 gtk_gesture_swipe_class_init (GtkGestureSwipeClass *klass)
 {
   GtkGestureClass *gesture_class = GTK_GESTURE_CLASS (klass);
+  GtkEventControllerClass *event_controller_class = GTK_EVENT_CONTROLLER_CLASS (klass);
   GObjectClass *object_class = G_OBJECT_CLASS (klass);
 
   object_class->finalize = gtk_gesture_swipe_finalize;
 
+  event_controller_class->filter_event = gtk_gesture_swipe_filter_event;
+
   gesture_class->update = gtk_gesture_swipe_update;
   gesture_class->end = gtk_gesture_swipe_end;